Thursday, May 20, 2010

Phantasmal Frogs and Epibatidine

News Reported yesterday that an endangered species of poison dart frog was successfully breed in captivity at the Blue Reef Aquarium in Portsmouth England. The Phantasmal poison frog (Epipedobates tricolor) is a species of poison dart frog. Their natural habitat is the Andean slopes of the central Ecuadorian Bolívar province. They have radiant color, powerful poison, and yet are some of the smallest frogs around, ranging from 1-4 cm. A chemical extracted from the skin of this species has turned out to be a painkiller 200-times as potent as morphine, called epibatidine. However, epibatidine acts on central nicotinic acetylcholine receptors in the brain and not Mu receptors like Morphine and Fentanyl. Therefore, Naloxone or Narcan does not reverse its action. I am really not sure why breeding this frog is news. It was my understanding that the problem wasn't breeding, but having the captive frogs still produce the toxin in their skin.

Epibatidine can be synthesized and several analogs have been created and tested in Europe. azabicyclo[2.2.1]heptane is the active part on nicotinic receptors. However, none of these medicines like Tebanicline and Epiboxidine have proven both safe and effective. These analogs are less potent but don't suppress respirations. One problem with opioid analgesia like codeine, hydrocodone and morphine is that these do very little for neurogenic pain like back pain. Research sugests that future pain medicines based on Epibatidine are effective against neuropathic as well as somatic pain.

I hope we don't see this sort of thing as a weapon. Its antidote is mecamylamine (Inversine). However repeat exposure produces increased sensitivity and not tolerance.4"-fluoro analogue of the 3R,4S,βS isomer of ohmefentanyl is the most potent opioid yet discovered, possessing an analgesic potency approximately 18,000-fold greater than morphine. Carfentanyl is also a powerful opioid.

1 comment:

Naowarat said...

Hi, I just read the article about epibatidine ( and the author wrote that ..."Dr. Daly was forced to try and breed the frogs in captivity. Although the frogs survived, their skins did not contain the compound with the analgesic effect. It is possible therefore the frogs do not biochemically produce it, but may ingest it in their natural habitat, extracting then secreting it..."

I just wonder whether the frogs breed outside their natural habitat can still produce epibatidine or not.